Well, this seems rather un-Rockstar-like. Grand Theft Auto Online, which will be free to owners of the ultra-successful GTA V, has been in closed beta testing since just after the main game's release. Of course, just because it's closed doesn't mean that we won't learn all about it before its public release. So far, one of the most interesting leaks involves ingame transactions, which will include consumables and ingame currency.
Apparently, nothing substantial from your single-player campaign will carry over to the online campaign. You'll start from square one, committing crimes to be able to afford that luxury house, car and whatever else you might want to pamper yourself with. If you're feeling that your progression is a bit slow, you can fix it by hauling out your wallet.
Four pricing tiers exist for the ingame currency, but the best value - no surprise - is the most expensive package. It's priced at £13.49 (~$22 USD), and gives you $1,250,000 to spend ingame. To put that into perspective, the most expensive residence in the game will cost $400,000, so it seems like $1.25 mil could get you far. But still - ingame purchases in a Rockstar game? That's not going to rub a lot of fans the right way, especially after the loyalty that fanbase has shown it.